1. Field of the Invention
This invention relates to a heater assembly and in particular to a retainer bracket for mounting a heating coil of the heater assembly and to a method for manufacturing the retainer bracket.
2. Related Art
Heating assemblies having coil-type heating elements are generally formed by passing the coil element, usually in a serpentine manner, through ring or grommet-type insulators which are supported by a metal retainer bracket. The object of the manufacture of these retainer brackets is to provide a rigid, and therefore reliable, retainer bracket at the lowest cost in materials, labor, and tooling.
A common method of producing the retainer bracket is to advance a piece of sheet metal through a plurality of work stations, such as in a progressive die machine, whereby particular features of the retainer bracket are formed at each station. Typically, once the sheet metal is deformed through stamping, side supports are connected by rivets or screws to the stamped structure for the purpose of increasing rigidity of the completed retainer bracket. Using fasteners to secure the side supports increases the overall material costs in assembling the retainer bracket and increases the cost of manufacture thereof.
It is paramount to the integrity of the assembly of the retainer bracket that the particular structure that receives and retains the heating coils be rigidly attached to the retainer bracket. More specifically, when that particular structure is not integral to the support structure, overall rigidity and reliability of the retainer bracket is lessened and the costs of manufacture are increased.
For example, U.S. Pat. No. 3,952,409 to Allison et al. teaches a bracket for an electric heating assembly comprising a pair of parallel side supports which mount several separate U-shaped transverse supports interlocked with the side supports by a tab-in-slot arrangement. The U-shaped supports have a pair of spaced side walls which form a recess for receipt of several insulator blocks which are held in place by tabs bent over a tab on each of the insulator blocks.
U.S. Pat. No. 3,992,609 to Alexander discloses a bracket very similar to that shown in the Alexander '609 patent but wherein the U-shaped supports for the insulator blocks are formed integral with the side supports. A planar, undeformed connecting piece of material extends between the side supports and the U-shaped supports to provide support between the respective components of the bracket.
However, these and other prior art attempts still require additional manufacturing cost as well as require additional material and fasteners for assembly of the heating coil retainer bracket with sufficient structural strength.